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Topic Review (Newest First)

07-31-2012 07:17 AM

T-bucket23

150 is still a little low, I like to see about 200-210 in hot weather, but it should work. Your compressor could be getting a little tired.

07-30-2012 08:28 PM

Ghetto Jet

Thanks for the quick reply LATECH. I checked this thread on my phone while I was out and grabbed a 12oz can on my way home. I just put it in and it brought my low pressure up to about 41, my high pressure was showing around 140 initially and 150 at the end of the can. The air temps came down considerably and my lines to the accumulator are finally condensating. I also found the manual control for the blend door in the dash with my hand and it was fully closed. Though I'm still convinced there is something else not working properly since my recirculate control doesn't increase fan speed and lower temps like it should. Also, I still can't get the compressor to give me that bogged feeling like it's fully engaged when I accelerate from a stop. It always use to feel like a dropped an anchor around 15 mph and there was no mistaking the sound.

Doing some reading I found out that I have the variable displacement V-5 compressor that has a mechanism that incorporates five axially oriented pistons and a variable angle wobble plate. Compressor displacement (piston stroke length) is controlled by the position of a bellows-actuated control valve in the rear head of the compressor. The control valve senses suction (low side) pressure. The difference between suction and crankcase pressure determines wobble plate angle, which in turn determines piston stroke and displacement.

I read the V5 compressor needs at minimal 47 psi to work properly. I'm thinking maybe what determines the displacement is malfunctioning due to inadequate low pressure. Perhaps it is not going to full displacement once the rpms are up when I'm driving. This could explain why I don't feel/hear the compressor like I always have previously when accelerating from a stop. I'll get another can and test it out.

Thanks for the help so far everyone.

07-30-2012 05:20 PM

LATECH

It needs another can of freon.You may need to spray the condenser with a hose some to help cool it off, to get it to take freaon, and to help stabilize the duct temp quicker.

07-30-2012 05:10 PM

Ghetto Jet

Pressures at idle 29 low 150 high, if I wind the throttle up to the low RPM rev-limiter the low pressure goes high into the danger zone before the compressor releases. According to the gauge set my idle numbers are just in the acceptable range. The A/C lines that wrapped in heat shield are hot and one small line running up towards the accumulator (not the large one going into it) is ice cold. The Accumulator itself feels ambient and there is no condensation on it after running for 20 or so minutes. Something strange I noticed while leaning in and out of the car, the a/c vent to the left of the steering wheel is putting out colder air than all the other upper and lower vents. I'm starting to think this may be some type of HVAC system issue since I'm already having a problem with Recirculate not behaving as it should.

07-29-2012 01:48 PM

LATECH

The cavalier has an orifice. If it is plugged , the low side would read very low or it would read into a vacuum.
The orifice may be permanent inside the line, I dont recall. it could also be at the high side tube at the inlet of the evaporator.(most Likely)

07-29-2012 01:45 PM

LATECH

If you hooked a can on with a gauge for the low side only, then you cant tell much. The compressor may not be pumping well, which would make the low side read high, and not take freon.Your just going to have to hook on a gauge set to figure it out.

07-29-2012 10:50 AM

Ghetto Jet

Quote:

Originally Posted by 2old2fast

How do you know the system is charged if you haven't put gauges on it ??
dave

I hooked up a can with with a gauge on it, it showed full and wouldn't take any freon. Earlier I meant I don't have dual gauges to check hi/low pressure.

Quote:

Originally Posted by cobalt327

Have you checked the lines under hood for icing?

Anyway, some common problems I have had were restricted orifice tube and being overcharged. I don't even know if your system uses a tube or not.

FWIW there are do-it-yourself recharge kits that include a pressure gauge on the refrigerant bottle.

I didn't check for icing, but icing must take sometime to occur and I have this problem from start up. I'll check out the Cavalier forum and see if it has a tube.

Quote:

Originally Posted by T-bucket23

I would also check for air flow restrictions and make sure the cooling fan(s) are running at the proper speed.

The electric fan kicks in full blast when I turn the A/C on.

07-29-2012 09:02 AM

T-bucket23

I would also check for air flow restrictions and make sure the cooling fan(s) are running at the proper speed.

07-28-2012 06:45 PM

2old2fast

How do you know the system is charged if you haven't put gauges on it ??
dave

07-28-2012 05:21 PM

cobalt327

Quote:

Originally Posted by Ghetto Jet

Please bear with me as I try to explain this.

The Compressor clutch engages, the system is fully charged, but it isn't able to maintain cold or even cool air with the fan speed turned up on a hot day in the sun (only blower speeds 3 and 4 are working, a resistor went bad years ago) If you turn the knob to speed 1 or 2 and let the fan stop pushing air for about 5 seconds and then turn back to speed 3 you will get a cold burst of air that lasts only a few seconds. So I know that the car capable of making cold air.

This car has always had working A/C prior to this. I parked it for the winter/spring and it sat for about 6 months. Now I put it back on the road and the first thing I notice is the A/C is behaving oddly. Something else odd the clutch doesn't cycle on/off it just stays on. And when I put it on Max/recirculate the blower speed no longer increases and the air doesn't get cooler. Also, prior to this, with A/C on when I accelerated from a stop I could always feel/hear the compressor engage and bog the motor around 15MPH. That sounds weird, but that is how it has always been. Sitting this car always had mediocre A/C but once you started to accelerate it's as though the clutch went into full engagement around 15mph. It no longer does this and I think this is why the air is weak. Now the air is cooler sitting than it is moving. I swapped fuses and looked around under the hood but I'm not use to working on A/C systems so I'm not sure what to do next.

My three thoughts were the belt tensioner is getting weak and slipping slightly on the compressor, explaining why more rpms seems to weaken the air.

The compressor is not working properly.

There is something electrical causing this.

If this was my car I would just turn this into the winter beater instead of the summer beater. But I have my g/f driving 55 miles a day in it instead of her Wrangler which has no A/C. She can't look like a hot mess when she gets to work.

Have you checked the lines under hood for icing?

Anyway, some common problems I have had were restricted orifice tube and being overcharged. I don't even know if your system uses a tube or not.

FWIW there are do-it-yourself recharge kits that include a pressure gauge on the refrigerant bottle.

07-28-2012 05:11 PM

LATECH

On a hot day, say 90 degrees, system running for 5-6 minutes and stabilized, i would say 210 high side 35-45 low side would seem about normal.

07-28-2012 05:02 PM

Ghetto Jet

Quote:

Originally Posted by LATECH

The only way to properly diagnose the AC is to put on a gauge set and check the pressures.
Its a good chance your compressor is not pumping well.

I can get my hands on a set, do you know what # ranges I should be seeing?

Boothboy, I thought of that too, but I couldn't find it. I think since I can get cold air if I let it build up without the fan running then it working.

07-28-2012 04:07 PM

boothboy

You might also want to check your heater valve to make sure it's closing all the way.

07-28-2012 03:57 PM

LATECH

The only way to properly diagnose the AC is to put on a gauge set and check the pressures.
Its a good chance your compressor is not pumping well.

07-28-2012 03:24 PM

Ghetto Jet

Mysterious A/C problem on 98 Cavalier 2.2L.

Please bear with me as I try to explain this.

The Compressor clutch engages, the system is fully charged, but it isn't able to maintain cold or even cool air with the fan speed turned up on a hot day in the sun (only blower speeds 3 and 4 are working, a resistor went bad years ago) If you turn the knob to speed 1 or 2 and let the fan stop pushing air for about 5 seconds and then turn back to speed 3 you will get a cold burst of air that lasts only a few seconds. So I know that the car capable of making cold air.

This car has always had working A/C prior to this. I parked it for the winter/spring and it sat for about 6 months. Now I put it back on the road and the first thing I notice is the A/C is behaving oddly. Something else odd the clutch doesn't cycle on/off it just stays on. And when I put it on Max/recirculate the blower speed no longer increases and the air doesn't get cooler. Also, prior to this, with A/C on when I accelerated from a stop I could always feel/hear the compressor engage and bog the motor around 15MPH. That sounds weird, but that is how it has always been. Sitting this car always had mediocre A/C but once you started to accelerate it's as though the clutch went into full engagement around 15mph. It no longer does this and I think this is why the air is weak. Now the air is cooler sitting than it is moving. I swapped fuses and looked around under the hood but I'm not use to working on A/C systems so I'm not sure what to do next.

My three thoughts were the belt tensioner is getting weak and slipping slightly on the compressor, explaining why more rpms seems to weaken the air.

The compressor is not working properly.

There is something electrical causing this.

If this was my car I would just turn this into the winter beater instead of the summer beater. But I have my g/f driving 55 miles a day in it instead of her Wrangler which has no A/C. She can't look like a hot mess when she gets to work.